The present invention relates generally to lighting systems which can be used to illuminate a desired area. More particularly, the present invention pertains to lighting systems with ventilation features to help ventilate a light source cavity.
Conventional lighting systems include a light source mounted on a substrate that is enclosed by a lens with the lens forming a cavity or space around the light emitter. When the lighting system is in use, the light source can produce a substantial amount of heat, which can raise the temperature inside the cavity or space. The increase in temperature produced by the light source can cause chemicals present in certain components of the lighting system such as adhesives, flux residues, or resins, to produce harmful gases. The gases produced can cause the lens of the lighting system to fog or discolor. The fogging or discoloration of the lens can attenuate the light passing through the lens, which can undesirably affect the illuminated appearance or overall light output of the lighting system. This problem is particularly prevalent in LED lighting systems, as LEDs conventionally produce a large amount of heat during operation.
In an attempt to combat this light attenuation, some conventional lighting systems may include a vent through an outer or top portion of the lens itself. Additionally, the vent in the lens includes a permeable material that allows the gases created during operation of the lighting system to escape. However, the cost of the permeable material as well as the difficulty in correctly placing and verifying proper placement of the vent directly in the lens is very high. Another disadvantage of these solutions is that the vent and the material inside the vent can distort the lit appearance or detract from the uniformity of the optical pattern of the lighting apparatus.
Additionally, many conventional lighting systems include a housing which can hold the other components of the lighting system. To improve thermal performance of the lighting systems, a heat management system or heat sink can be connected to the housing to dissipate heat away from the lighting apparatus, and particularly the substrate and the light source. However, several thermal interfaces can be positioned between the heat sink and the substrate, such that heat dissipating from the substrate must traverse several thermal interfaces before being dissipated to the heat sink. Such a configuration can make the thermal management system less efficient.
What is needed, then, are improvements in conventional lighting systems.